• format: lecture and discussion
• slides: introduction and overview
• software: need list of all software
• data: none
• other: none
• time: 30 minutes
• questions:
  • the goal ... alcohol shops map app? other ideas: bus stops
  • introduction to GIS and GeoData. familiar with GMapsAPI, but nothing more.
  • what are limits to google maps

Creating Geo Data

Working with Geo Data

Visualizing Geo Data

Building Apps with Geo Data

Goal: an location based app!

Github repo of the slides and some materials

https://github.com/mikelmaron/Cartonama

The LiveBoot ISO

http://aeneous.coolwrks.com/sajjad/Cartonama-Workshop-Hasgeek.iso

Workshop Schedule

http://workshop.cartonama.org/

Mailing List

http://groups.google.com/group/cartonama-workshop

Came away with a solid base understanding of what OpenStreetMap is all about ... the motivations and the approach.

• format: lecture
• slides: basic OSM intro
• software:
• data:
• other:
• time: 30 minutes
• questions:
  • license

Collaborative Global Mapping, "like Wikipedia for Maps"

the openstreetmap "one-liner"

http://www.youtube.com/watch?v=fpHKb-SZRh8

Immediate recovery, ongoing reconstruction

250,000 people, 2.5 km2

Hyper local, geotagged reporting, using Ushahidi

http://voiceofkibera.org/

Open License

Technical Freedom

Community

http://blog.foursquare.com/2012/02/29/foursquare-is-joining-the-openstreetmap-movement-say-hi-to-pretty-new-maps/

Understand how to use a GPS and collect data for OSM

• format: workshop
• slides:
• software:
• data:
• other: GPS units. Maybe Apps?
• time: 1 hour
• questions:
  • theory and practice
  • mobile: periodicity and accuracy. but what to use ... Android: MyTracks, others. OSMAnd --- unusable. what do they use in jbad?
  • POIs are not collected nearby to CIS ... street hawkers
  • MyTracks: can adjust frequency. gpx visible as mounted drives. uses GMaps as a basemap

Using the GPS

• Turn on GPS
• Get a Signal
• Page to Map
• Zoom and Pan
• Record WayPoints by pushing joy stick straight in
• Note Waypoint number

Record Data

• Type of highway and names
• Any interesting POI
• Parking
• Street Direction (one way street)‏
• Land use
• Walking paths, Cycleways, other routes
• Specific Buildings and Amenities
• Crossings, bridges, and tunnels
• Additional Noteworthy Places and Landmarks

• Tracks are recorded automatically
  • The track is a guideline, not the map!
• Can use pen/paper, camera, dictaphone, mobile, etc
• Work together to divide up the Cake!

Use of GPSBabel to download GPS data

• format: workshop
• slides: just show the commands
• software: gpsbabel, drivers
• data: results in GPX
• other:
• time: 20 minutes

• Connect GPS with USB cable

  !sh sudo gpsbabel -i Garmin -f usb: -o gpx -F waypoints.gpx

• Change to USB Mode ... shows up as a drive
• or add -t to gpsbabel command

• http://mapas.alternativaslibres.es/downloads.php
• mkgmap

Facility with JOSM and Potlatch editors.

• format: workshop
• slides: maybe some JOSM screenshots
• software: JOSM. Potlatch?
• data: results in OSM
• other:
• time: 40 minutes
• questions:

Understand Tagging, Map Features, Editing Presets in JOSM and Potlatch

• format: lecture
• slides: needed
• software:
• data:
• other:
• time: 30 minutes
• questions: how to generate interest

http://wiki.openstreetmap.org/wiki/Map_Features

highway = bus_stop
name = Domlur
name:en = Domlur
name:kn = ಡೊಮಲೂರು

http://www.openstreetmap.org/browse/changeset/10839653

• simple data format
• tagging for metadata
• standard map tiles
• full planet dumps = thriving ecosystem of tools, renderers, editors, routers, applications

http://wiki.openstreetmap.org/wiki/APIs

• Main editing API. GET/PUT/DELETE/POST
• XAPI and Overpass GET
• Planet and minutely diffs XML files

http://wiki.openstreetmap.org/wiki/Develop

• Basics: http://learnosm.org/
• Using OSM: http://switch2osm.org/
• Book: http://www.openstreetmap.info/
• Wiki: http://wiki.openstreetmap.org/
• Lists, IRC

OSM bus stop data for Bangalore

http://open.mapquestapi.com/xapi/api/0.6/node[highway=bus_stop][bbox=77.4256,12.8254,77.7844,13.1396]

https://github.com/mikelmaron/Cartonama/blob/master/data/busstops-bangalore.xml

• Not perfectly round
• Not even regularly irregular
• An "oblate spheroid"
• spheroid versus geoid
• geodesy

• semi-major axis (equatorial)
• semi-minor axis (polar)
• common spheroids
  • World Geodetic Survey 1984 (WGS84)
  • WGS 1972
  • Everest 1830 and 1956
  • NAD 1927 and 1983

• Geographic: latitude and longitude in degrees
• Projected: easting and northing in meters
• False easting and northing
• Datum: coordinate system origin
• WHEN IN DOUBT, USE THE WGS84 SPHEROID AND DATUM

• Round(ish) world, flat map
• Project on the surface of another solid in some orientation, then unwrap
• Sacrifice shape, area, and/or direction
• Allows us to use Cartesian coordinates (whew!)

Azimuthal

Orthographic

• Unprojected, or Equirectangular
• Mercator
• Universal Transverse Mercator (UTM)
• Spherical or "Web" Mercator

• Originally implemented by Google
• Now standard across web mapping services
• By setting max lat to +/- 85.0511°, the world becomes square
• This has implications for tiling

• Projection + Spheroid + Datum + Units = SRS
• Also known as "coordinate reference systems" (CRS)

• European Petroleum Standards Group
• Established EPSG codes for common spatial reference systems
• Unprojected Longitude/Latitude: EPSG 4326
• Web Mercator: EPSG 3857
• UTM zone 43 North: EPSG 32643 (for example)

Raster Data

Vector Data

"Raster is faster but vector is correcter."

• Grid: columns x rows
• Cell values
  • Discrete
  • Continuous
  • Imagery
• Georeferencing via affine transformation

32.0
0.0
0.0
-32.0
691200.0
4576000.0

• A: x component of the pixel width (x-scale)
• D: y component of the pixel width (y-skew)
• B: x component of the pixel height (x-skew)
• E: y component of the pixel height (negative y-scale)
• C: x-coordinate of the center of the upper left pixel
• F: y-coordinate of the center of the upper left pixel

(example borrowed from Wikipedia)

• GeoTIFF (.tif)
  • World file (.wld, or .tfw)
  • Projection in "Well-Known Text" (.prj)
• World files for JPEGs, or PNGs (.jpw, .pgw)
• Others: BIL, JPEG2000, ECW, NITF, etc.

• The "Simple Features" Model
• Feature
  • Attributes
  • Geometry

• Point
• Line
• Polygon
• Multi-geometries

• x and y (and sometimes z)
• don't forget, longitude is x and latitude is y
• POINT(77.58 12.96)

• Just a sequence of Points
• LINESTRING(77.56 12.95, 77.57 12.95, 77.58 12.96)

• One or more closed rings
• A ring is a linestring that intersects only at the first and last points
• ∴ a square is represented with five points
• POLYGON((0 0, 0 1, 1 1, 1 0, 0 0))

• Polygons have one exterior ring and zero or more interior rings
• Interior rings are donut holes
• POLYGON((0 0, 0 4, 4 4, 4 0, 0 0), (3 3, 3 1, 1 1, 1 3, 3 3))

• Donut holes can have holes of their own
• Rings that mark included areas are clockwise
• Ring that mark donut holes are anti-clockwise
• This is to make area calculations work right

• ESRI Shapefile
• GML
• KML
• GeoJSON
• "Well-Known" Text (WKT) and Binary (WKB)
• GeoRSS
• GPX

• .shp
• .shx
• .dbf
• .prj
• others (e.g. .sbn, .xml, etc.)

http://geojson.org/

{ "type": "Point", "coordinates": [77.58, 12.96] }

{
    "type": "LineString",
    "coordinates": [ [100.0, 0.0], [101.0, 1.0] ]
}

{
    "type": "Polygon",
    "coordinates": [
        [ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ]
    ]
}

{ 
    "type": "Polygon",
    "coordinates": [
        [ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ],
        [ [100.2, 0.2], [100.8, 0.2], [100.8, 0.8], [100.2, 0.8], [100.2, 0.2] ]
    ]
}

{ 
    "type": "Feature",
    "geometry": {"type": "Point", "coordinates": [77.58, 12.96]},
    "properties": {"name": "Bangalore"}
}

N.B. Properties can be any legit JSON object!

{
    "type": "FeatureCollection",
    "features": [ ... ]
}

• A geospatial extension to PostgreSQL
• Geometry operations
• Spatial predicates
• Spatial indexes
• Spatial reference system support

Create a PostGIS template

$ createdb template_gis
$ createlang plpgsql template_gis
$ psql template_gis </usr/share/postgis/postgis.sql
$ psql template_gis </usr/share/postgis/spatial_ref_sys.sql

Make a spatial database from the template

$ createdb -Ttemplate_gis my_new_postgis_db

geometry_columns

      Column       |          Type          | Modifiers 
-------------------+------------------------+-----------
 f_table_catalog   | character varying(256) | not null
 f_table_schema    | character varying(256) | not null
 f_table_name      | character varying(256) | not null
 f_geometry_column | character varying(256) | not null
 coord_dimension   | integer                | not null
 srid              | integer                | not null
 type              | character varying(30)  | not null

spatial_ref_sys

  Column   |          Type           | Modifiers 
-----------+-------------------------+-----------
 srid      | integer                 | not null
 auth_name | character varying(256)  | 
 auth_srid | integer                 | 
 srtext    | character varying(2048) | 
 proj4text | character varying(2048) |

Create the table

CREATE TABLE poi (id SERIAL, name VARCHAR);

Add the geometry column

SELECT AddGeometryColumn('poi','location',4326,'POINT',2);

# \d poi
                   Table "public.poi"

  Column  |       Type        |         Modifiers
----------+-------------------+--------------------------------------
 id       | integer           | not null default nextval(...)
 name     | character varying | 
 location | geometry          |

Check constraints:
    "enforce_dims_location" CHECK (st_ndims(location) = 2)
    "enforce_geotype_location" CHECK
        (geometrytype(location) = 'POINT'::text OR location IS NULL)
    "enforce_srid_location" CHECK (st_srid(location) = 4326)

# INSERT INTO poi (name, location)
         VALUES ('CIS', 'POINT(77.6375384 12.9647134)');

ERROR:  new row for relation "poi" violates check constraint
        "enforce_srid_location"

# INSERT INTO poi (name, location)
         VALUES ('CIS', 'SRID=4326;POINT(77.6375384 12.9647134)');

INSERT 0 1

# SELECT * FROM poi;

 id | name |                      location                      
----+------+----------------------------------------------------
  2 | CIS  | 0101000020E61000006D7CDC6DCD685340A4062EEAEEED2940
(1 row)

# SELECT id, name, AsText(location) FROM poi;

 id | name |            astext            
----+------+------------------------------
  2 | CIS  | POINT(77.6375384 12.9647134)
(1 row)

• Equals
• Is Disjoint With
• Intersects
• Touches
• Crosses
• Is Within
• Contains
• Overlaps
• Covers
• Is Covered By

"Dimensionally Extended 9 Intersection Model" (DE-9IM)

• ST_Equals(geom1, geom2)
• ST_Disjoint(geom1, geom2)
• ST_Intersects(geom1, geom2)
• ST_Touches(geom1, geom2)
• ST_Crosses(geom1, geom2)
• ST_Within(geom1, geom2)
• ST_Contains(geom1, geom2)
• ST_Overlaps(geom1, geom2)
• ST_Covers(geom1, geom2)
• ST_CoveredBy(geom1, geom2)

$ shp2pgsql -s4326 -I world_borders.shp admin0 | psql my_db

               Table "public.world_borders"
   Column   |         Type          |   Modifiers                          
------------+-----------------------+------------------------------
 gid        | integer               | not null default nextval(...)
 cat        | double precision      | 
 fips_cntry | character varying(80) | 
 cntry_name | character varying(80) | 
 area       | double precision      | 
 pop_cntry  | double precision      | 
 the_geom   | geometry              |

Indexes:
    "world_borders_pkey" PRIMARY KEY, btree (gid)
    "world_borders_the_geom_gist" gist (the_geom)
Check constraints:
    "enforce_dims_the_geom" CHECK (st_ndims(the_geom) = 2)
    "enforce_geotype_the_geom" CHECK
        (geometrytype(the_geom) = 'MULTIPOLYGON'::text ...)
    "enforce_srid_the_geom" CHECK (st_srid(the_geom) = 4326)

# SELECT name, cntry_name FROM world_borders, poi
    WHERE st_contains(world_borders.the_geom, poi.location);

 name | cntry_name 
------+------------
 CIS  | India
(1 row)

• ST_Union(geom1, geom2)
• ST_Intersection(geom1, geom2)
• ST_Difference(geom1, geom2)
• ST_Buffer(geom, distance)
• ST_ConvexHull(geom)
• ST_Transform(geom, srid)
• ... and many more!

• ST_Distance(geom1, geom2)
• ST_Length(geom)
• ST_Area(geom)
• ST_Centroid(geom)
• ST_Distance_Spheroid(geom1, geom2)
• ... and many more!

SELECT SUM(ST_Area(ST_Transform(the_geom, 32643))) / 1000000
    FROM world_borders WHERE cntry_name = 'India';

?column?     
------------------
3196343.52393187
(1 row)

SELECT ST_Distance_Sphere(
        'POINT(77.6375384 12.9647134)', 'POINT(122.7 37.4)') / 1000;

?column?     
------------------
5216.69910277434
(1 row)

# EXPLAIN SELECT name, cntry_name FROM world_borders, poi
          WHERE st_contains(world_borders.the_geom, poi.location);

                         QUERY PLAN
----------------------------------------------------------------------
 Nested Loop  (cost=0.00..1347.15 rows=1 width=14)
   Join Filter: ((world_borders.the_geom && poi.location) AND
                 _st_contains(world_borders.the_geom, poi.location))
   ->  Seq Scan on poi  (cost=0.00..1.01 rows=1 width=104)
   ->  Seq Scan on world_borders
                    (cost=0.00..352.84 rows=3784 width=6982)
(4 rows)

# CREATE INDEX world_borders_the_geom_gist
         ON world_borders USING GIST (the_geom);

# EXPLAIN SELECT name, cntry_name FROM world_borders, poi
          WHERE st_contains(world_borders.the_geom, poi.location);

                         QUERY PLAN
----------------------------------------------------------------------
 Nested Loop  (cost=0.00..1815.00 rows=5 width=42)
   Join Filter: _st_contains(world_borders.the_geom, poi.location)
   ->  Seq Scan on poi  (cost=0.00..18.30 rows=830 width=64)
   ->  Index Scan using world_borders_the_geom_gist on world_borders
        (cost=0.00..1.90 rows=1 width=6982) 
         Index Cond: (the_geom && poi.location)
(6 rows)

$ pgsql2shp my_db poi

Initializing... Done (postgis major version: 1).
Output shape: Point
Dumping: XX [1 rows].

A F/OSS library that speaks dozens and dozens of formats

• GDAL is for raster data
• OGR is for vector data

$ gdalinfo SRTM_fB03_n012e077.tif

Driver: GTiff/GeoTIFF
Files: SRTM_fB03_n012e077.tif
Size is 1201, 1201
Coordinate System is:
GEOGCS["WGS 84",
    DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.257223563,
            AUTHORITY["EPSG","7030"]],
        AUTHORITY["EPSG","6326"]],
    PRIMEM["Greenwich",0],
    UNIT["degree",0.0174532925199433],
    AUTHORITY["EPSG","4326"]]
Origin = (76.999583333333334,13.000416666666666)
Pixel Size = (0.000833333333333,-0.000833333333333)
Corner Coordinates:
Upper Left  (  76.9995833,  13.0004167) ( 76d59'58.50"E, 13d 0' 1.50"N)
Lower Left  (  76.9995833,  11.9995833) ( 76d59'58.50"E, 11d59'58.50"N)
Upper Right (  78.0004167,  13.0004167) ( 78d 0' 1.50"E, 13d 0' 1.50"N)
Lower Right (  78.0004167,  11.9995833) ( 78d 0' 1.50"E, 11d59'58.50"N)
Center      (  77.5000000,  12.5000000) ( 77d30' 0.00"E, 12d30' 0.00"N)
Band 1 Block=1201x1 Type=Float32, ColorInterp=Gray

gdal_translate

$ gdal_translate -of GTiff some_other_format.jpg a_better_format.tif

$ gdal_translate --formats

gdalwarp

$ gdalwarp -t_srs EPSG:3875 some_file_in_4326.tif web_mercator.tif

gdaladdo

$ gdaladdo satellite_image.tif 2 4 8 16 32

$ ogrinfo world_borders.shp

INFO: Open of `world_borders.shp'
      using driver `ESRI Shapefile' successful.
1: world_borders (Polygon)

$ ogrinfo world_borders.shp

Layer name: world_borders
Geometry: Polygon
Feature Count: 3784
Extent: (-180.000000, -90.000000) - (180.000000, 83.623596)
Layer SRS WKT:
(unknown)
CAT: Real (16.0)
FIPS_CNTRY: String (80.0)
CNTRY_NAME: String (80.0)
AREA: Real (15.2)
POP_CNTRY: Real (15.2)

OGRFeature(world_borders):0
  CAT (Real) =                1
  FIPS_CNTRY (String) = AA
  CNTRY_NAME (String) = Aruba
  AREA (Real) =          193.00
  POP_CNTRY (Real) =        71218.00
  POLYGON ((-69.882233 12.41111,-69.946945 12.436666, ...))

Assigning SRS

$ ogr2ogr -a_srs epsg:4326 world_borders_4326.shp world_borders.shp

Transforming SRS

$ ogr2ogr -a_srs epsg:4326 -t_srs epsg:3875 world_borders_3875.shp world_borders.shp

Format conversion

$ ogr2ogr -f KML world_borders.kml world_borders.shp

Database support

$ ogr2ogr -f PostgreSQL PG:dbname=my_db world_borders.kml

• API

  $ curl http://api.openstreetmap.org/api/0.6/map?bbox=-0.5,51.25,0.5,51.75

  (only returns 50,000 objects)

• XAPI

  • Fewer limits
  • Allows filtering by tags
  • Dog slow

• Formats

  • XML
  • Protocol Buffers (PBF)

• Planet.osm

  • http://planet.openstreetmap.org/
  • Full size: 20GB compressed
  • Weekly changesets: 400MB
  • Hourly and minutely changes

• Planet Extracts
  • http://download.geofabrik.de/
  • http://download.cloudmade.com/
  • http://metro.teczno.com/

Lat/Lon import

$ osm2pgsql -l -d my_db -s -G planet.osm.bz2

Mercator import

$ osm2pgsql -m -d my_db -s -G planet.osm.bz2

Partial import

$ osm2pgsql -l -d my_db -b -0.5,51.25,0.5,51.75 planet.extract.osm.bz2

Important flags

• -l / -m = 4326 vs 3875
• -s = "slim mode"
• -G = compute multi-geometries
• -b minlon,minlat,maxlon,maxlat = geographic extract

• "Style" dictates which tags get turned into columns

• Default lives in /usr/share/osm2pgsql/default.style or similar

  # OsmType  Tag          DataType     Flags
  node,way   note         text         delete
  node,way   source       text         delete
  node,way   created_by   text         delete
  node,way   access       text         linear
  node,way   admin_level  text         linear
  node,way   aerialway    text         linear
  node,way   aeroway      text         polygon
  ...
  

• planet_osm_line: contains all imported ways
• planet_osm_point: contains all imported nodes with tags
• planet_osm_polygon: contains all imported polygons
• planet_osm_roads: contains just the roads

http://wiki.openstreetmap.org/wiki/Osmosis

Create a local API database

osmosis --read-xml file="planet.osm" --write-apidb database="x"

Apply a diff to an OSM file

osmosis --read-xml-change file="planetdiff-1-2.osc"
        --read-xml file="planet1.osm"
        --apply-change --write-xml file="planet2.osm"

Extract specific key value pairs

osmosis --read-xml city.osm 
        --way-key-value keyValueList="railway.tram,railway.tram_stop"
        --used-node --write-xml city_tram.osm

Extract a bounding box

bzcat downloaded.osm.bz2 | osmosis\
    --read-xml enableDateParsing=no file=-\
    --bounding-box top=49.5138 left=10.9351 bottom=49.3866 right=11.201
    --write-xml file=-\
   | bzip2 > extracted.osm.bz2

http://wiki.openstreetmap.org/wiki/Osmium

/*
  run with: osmjs -l sparsetable -j extract-nodes.js OSMFILE
*/

wanted_keys = [ ... ];

Osmium.Callbacks.node = function() {
  if(!this.tags["name"] && !this.tags["place_name"]) return;
  found_wanted_keys = false;
  for (var i = 0; i < wanted_keys.length; i++) {
    if (this.tags[wanted_keys[i]]) {
        found_wanted_keys = true;
        break;
    }
  }
  if (!found_wanted_keys) return;
  print(JSON.stringify({
    "geom": [this.geom.lon, this.geom.lat],
    "tags": this.tags, 
    "type":"node", 
    "id": this.id
    })
  )
}

var shp_pois = Osmium.Output.Shapefile.open('./pois', 'point');
shp_pois.add_field('id', 'integer', 10);
shp_pois.add_field('type', 'string', 32);
shp_pois.add_field('name', 'string', 32);

var node_tags = {
    amenity: { restaurant: 'restaurant', pub: 'pub' },
    shop: { supermarket: 'supermarket' }
}

(continued...)

Osmium.Callbacks.node = function() {
    for (var key in this.tags) {
        if (node_tags[key]) {
            var type = node_tags[key][this.tags[key]];
            if (type) {
                shp_pois.add(this.geom, {
                    id: this.id,
                    type: type, 
                    name: this.tags.name
                });
            }
        }
    }
}

Osmium.Callbacks.end = function() {
    shp_pois.close();
}

TIRED YET?

Results

https://github.com/mikelmaron/Cartonama/blob/master/data/bangalore-bus-shp.zip

What are Map Tiles?

• format: lecture
• slides: what are tiles about
• software:
• data:
• other:
• time: 15 minutes
• questions: more interest in this ** nice graphics needed for tile pyramid

Creating Tiles w/ TileMill

• format: tutorial
• slides: adding data, carto, mapbox
• software: tilemill
• data: Shapefiles and/or PostGIS. result in tiles.
• other:
• time: 1.5 hours
• questions: what can we get from devseed ** show how to generate_tiles.py from mapnik style sheets output by tilemill
• connect to shapefile, postgis db
• overlay on preset osm tiles. render osm data itself
• render raster data as well

• format: tutorial?
• slides:
• software:
• data: need to make sure data collected and processed into shapefile includes translations
• other:
• time: 30 minutes
• questions: really try to show this, though it might be tricky

@futura_med: "Kedage Normal", "Futura Medium","Function Pro Medium","Ubuntu Regular","Trebuchet MS Regular","DejaVu Sans Book","unifont Medium";

#bus_stops {
  marker-width: 2;
  marker-line-color: #00f;
  text-fill: #b50d38;
  text-name: "[name_kn]";
  text-face-name: @futura_med;
  text-size: 12;
  text-dx: 5;
  text-allow-overlap: false;  
}

https://tiles.mapbox.com/groundtruth/map/map-busd5lm5

Ways to serve tiles ... TileCache (for imagery), TileStash, MapBox, mod_tile, etc

• format: lecture
• slides: show the various ways and how to configure
• software:
• data:
• other:
• time: 30 minutes
• questions: hands on or?

https://tiles.mapbox.com/groundtruth/map/map-busd5lm5

survey Javascript Mapping APIs (OpenLayers, ModestMaps, GMaps API, Leaflet, Mapstraction)

• more interest in this
• format: lecture
• slides:
• software:
• data:
• other:
• time: 30 minutes
• questions: survey the options, and pick one

leaflet and discussion

Geocoding and Location Queries

• format: workshop
• slides: basic geocoding apis. and a basic location query proxy?
• software:
• data:
• other:
• time: 45 minutes
• questions: more interest in this. is there a small postgis->geojson web service? maybe flask, or node.js. python would have postgis bindings

show nominatim, geonames, overpass api

Create an app using, tiles and search, generated from the collected data.

• format: workshop
• slides: instructions
• software: html, css, js.
• data: tiles, database. this results in the app.
• other:
• time: 1.5 hours
• questions: would be nice to have this app built.

https://github.com/yuvipanda/POSM http://yuvi.in/POSM/

• there is a session on this in "Working"

• could simply be a lecture during part 4.

• part of Javascript Mapping APIs, or earlier during OSM?

• http://phonegap.com/ ? part of part 4 extra credit?
• https://github.com/yuvipanda/POIOSM

• Django, Drupal, Rails